Many herbicides require the addition of an adjuvant to the spray mixture to provide wetting and spreading on foliar surfaces. Often that adjuvant is a surfactant, which can perform a variety of functions, such as increasing spray droplet retention on difficult to wet leaf surfaces, or to provide penetration of the herbicide into the plant cuticle. These adjuvants are provided either as a tankside additive or used as a component in herbicide formulations.
Gaskin, et al., (Pestic. Sci. 1993, 38, 185-192) demonstrated that some trisiloxane ethoxylates (TSE), such as Silwet L-77(copyright) surfactant (available from OSi Specialties, Inc. of Greenwich, Conn.), can antagonize cuticular penetration of a herbicide into grasses, when compared to the herbicide alone. The term antagonism is used to indicate that the treatment of herbicide plus adjuvant is less effective than the comparative herbicide treatment.
Gaskin, et al., (Pest. Sci. 1993, 38, 192-200) showed that this antagonism can be mitigated if the number of ethylene oxide (EO) units contained in the TSE is increased to 17 or more; however, superspreading of the TSE is reduced dramatically once the degree of ethoxylation exceeds about 12 EO, and TSE""s containing the higher EO adducts show spreading properties similar to conventional nonsilicone surfactants.
Sandbrink, et al., (Pest. Sci. 1993, 38, 272-273) published that a TSE antagonized glyphosate performance relative to glyphosate alone in the control of Panicum maximum Jacq. Snow, et. al., Langmuir, 1993, 9, 424-30, discusses the physical properties and synthesis of novel cationic siloxane surfactants. These siloxanes are based on the reaction of a chloropropyl modified trisiloxane with an alkanolamine, such as N-methylethanolamine, which was further reacted with a halide to make a quaternary surfactant.
Petroff, et al., (EP 92116658) describes the use of cationic, quaternary trisiloxanes to enhance the efficacy of glyphosate on velvetleaf, a broadleaf weed. Henning, et al., (DE4318537) describes cationic siloxanyl modified polyhydroxy hydrocarbon or carbohydrate for use with plant protection agents. These compounds are derived from a saccharide containing 1 to 10 pentose and/or hexose units, modified with a quaternary ammonium group, and a siloxane moiety.
Reid, et al., (U.S. Pat. No. 3,389,160) describes amino modified siloxane alkoxylates where the amino functionality appears as the terminal group on the alkyleneoxide moiety, opposite the siloxane group.
Policello in PCT WO 97/32475 discloses amino modified siloxanes wherein the amine is bound by an ether bond to the siloxane backbone wherein the amine may be terminal or pendant to the backbone.
The present invention teaches the composition of terminally modified, amino, polyether, siloxanes, known henceforth as amino siloxane alkokylates, and their use as adjuvants. The amino siloxane alkoxylates of the present invention enhance the efficacy of agrichemicals on plants as compared to conventional TSE""s alone. Optionally, the amino siloxane alkoxylates of this invention may be blended with conventional trisiloxane alkoxylates. Blends of these unique amino siloxanes with more traditional trisiloxane alkoxylates (TSA) provide superspreading properties, on difficult to wet surfaces, that are equal to, or greater than what is contributed by the individual components.
These compositions are especially useful in overcoming the antagonistic effects on pesticide efficacy associated with superspreading, TSAs. Mixtures of the compositions of the present invention with TSAs provide enhanced spreading properties relative to the individual components alone. In addition, these products provide a low aqueous surface tension (xe2x89xa625 mN/m at 0.1 wt %), which is desirable for enhanced spreading of pesticide solutions.
Composition
The amino siloxane alkoxylates of the present invention have the average general formula:
ZMe2SiO[(Me)2SiO]x SiMe2Q,
wherein x=0 to 2, preferably 1, Q=CaH2aO(C2H4O)b(C3H6O)cR, a=2 to 4, preferably 3, b=1 to 12, preferably 3 to 8, c=0 to 5, providing that when c is greater than 0, (b+c)=2 to 12, preferable=4 and 8, R is hydrogen, acetyl or a hydrocarbon radical between 1 and 4 carbon atoms, Z is BN[DO(CdH2dO)eR]2xe2x88x92ZVz each d is 2 to 4, preferably 2 to 3, each e is 0 to 15, preferably 0 to 8, z=0 to 2, preferably 2, each V is a univalent group, D is an alkylene divalent bridging group on which there may be hydroxyl substituents, and B is a divalent bridging group.
V groups preferably are alkyl (which may be branched, linear or cyclic) of less than 8 carbons, which may or may not contain hydroxyl functionalities. Another preferred V is an alkyl amine functionality, the nitrogen of which may be further substituted (e.g. with an alkyl) or be further alkoxylated. Exemplary V are ethyl, 2-hydroxyethyl, 3-hydroxypropyl, methyl, and 2-aminoethyl.
B groups may be of the formula D(O)y(CdH2dO)jD wherein D and d are as above, j=0 to 8, preferably 0 to 2, and y=0 or 1. Preferably D has 2 to 6 carbon atoms. B may also preferably be a divalent alkylene group of C2-C4.
When Q or B is a mixture of oxyalkylenes, it may be blocked or random. One skilled in the art will understand the advantages in the position of the oxyethylene relative to the oxypropylene, when the alkyleneoxide group is blocked.
The Z groups may include protonated amines, i.e, where there is a hydrogen ion attached to the nitrogen in the Z group, which can occur to the amino siloxane alkoxylates under acidic conditions. Also contemplated herein are quaternary versions of Z, i.e., where there is a third R3 group on the nitrogen in Z, but said quaternary compounds are not preferred for use in the present invention.
Preferred Z structures are wherein R is hydrogen or methyl, D is a divalent organic group of 2 to 4 carbons, B is a divalent organic group of 2 to 4 carbons, in which at least one carbon radical contains a hydroxyl group, and V is 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, propyl, ethyl or methyl. Preferred amino siloxane alkoxylates are trisiloxanes.
In addition the compositions of the present invention optionally may include nonionic siloxane alkoxylates of the general formula:
R4Me2SiO[MeSi(G)O]gSiMe2R4 
wherein g=0 to 2, preferably 1.
G=CaH2aO(C2H4O)t(C3H6O)wR.
and R are as above, t=3 to 12, preferably 4 to 8
w=0 to 8, providing that when w is  greater than 0, (t+w) is preferably between 5 and 12. R4 is G, or an alkyl of one to four carbons. The preferred nonionic siloxane alkoxylates are trisiloxane alkoxylates, where g=1, d=3, t=4 to 8, w=0, R4 is Me, R is H or Me.
The compositions of the present invention also optionally include ingredients for use herein are pesticides, especially acid functionalized ones, i.e., compounds that contain at least one carboxylic, sulfonic or phosphonic acid group or their salt or ester. The term pesticide means any compound used to destroy pests, e.g., rodenticides, fungicides, and herbicides. Illustrative examples of pesticides which can be employed include, but are not limited to, growth regulators, photosynthesis inhibitors, pigment inhibitors, mitotic disrupters, lipid biosynthesis inhibitors, cell wall inhibitors, and cell membrane disrupters. The amount of pesticide employed in compositions of the invention varies with the type of pesticide employed. More specific examples of pesticide compounds that can be used with the compositions of the invention are: phenoxy acetic acids, phenoxy propionic acids, phenoxy butyric acids, benzoic acids, triazines and s-triazines, substituted ureas, uracils, bentazon, desmedipham, methazole, phenmedipham, pyridate, amitrole, clomazone, fluridone, norflurazone, dinitroanilines, isopropalin, oryzalin, pendimethalin, prodiamine, trifluralin, glyphosate, sulfonylureas, imidazolinones, clethodim, diclofop-methyl, fenoxaprop-ethyl, fluazifop-p-butyl, haloxyfop-methyl, quizalofop, sethoxydim, dichlobenil, isoxaben, and bipyridylium compounds.
Manufacture
The amino siloxane alkoxylates of the present invention may be made by the hydrosilation of a terminal hydridosiloxane with allyl glycidal ether, and allyl started polyalkyleneoxide. This is followed by ring opening of the epoxide moiety with a primary or secondary amine. The components described are available commercially and may be made as known in the art. Alternatively, the hydrosilation may take place with an allyl amine and an allyl started polyalkyleneoxide. Hydrosilation reaction conditions may be found in Marcienic, ed., 122-23 and 558-568 (1995), which is incorporated herein.
The amine intermediate (e.g., allyl amine) may be prepared by reaction of an unsaturated halide (e.g., allyl bromide) and an amine. The allyl amine also may be prepared by reaction of an allyl glycidyl ether (or similar unsaturated epoxide) with an amine (which result in an ether bond in the bridging group B). An alternative method uses aziridine, which is not preferred for toxicity reasons, are disclosed in PCT US97/04128, which is incorporated herein by reference.
The hydrosilation products may be blends of the product of the present invention with amine terminated siloxanes and polyether terminated siloxanes. If desired, one may separate these, e.g., by distillation; however, these blends may be used without such purification.
The nonionic siloxane and the pesticides are available commercially and their manufacture is known in the art.
Use
The amino siloxane alkoxylates primarily are intended for use in the agricultural field as adjuvants for pesticide containing aqueous formulations. The composition of the present invention is useful as a tank side additive, or as a component in a herbicide formulation. In addition the compositions of the present invention are useful as adjuvants for other pesticides, such as, fungicides, insecticides, plant growth regulators, acaracides and the like.
The siloxanes are added directly to a spray tank along with an acid functional pesticide, or as part of a pesticide formulation. When used as a tankside additive, the amino siloxane alkoxylates are present at weight concentrations between 0.01% and 5.0%, preferably between 0.025% and 0.5%. Likewise, when the aminosiloxane alkoxylates are used in a pesticide formulation (In-can), they are present at weight concentrations that will deliver between 0.01% and 5.0% to the final use dilution, preferably between 0.025% and 0.5%, of the final use dilution.
It is noted that most dilutions will be made with water, but in the case of crop oil concentrates, oils will be the diluents.
When the compositions of the present invention are used in conjunction with a nonionic siloxane alkoxylate, the weight ratio of the nonionic siloxane alkoxylate to the amino siloxane alkoxylates is between 5:95 and 95:5, preferably between 5:95 and 40:60. The blend may be accomplished by physically mixing the two components together as a formulation, or by adding them separately to a spray mixture at point of use.
The amino siloxane alkoxylates also may be used generally as surface active agents in aqueous formulation where there is an acid functionalized component. The amino siloxane alkoxylates of the present invention also may be used generally as surface active agents, including, but not limited to, surfactants, wetting agents and softeners for textiles, as flowing and leveling agents in coatings, in hair care products, skin care and creams for personal care applications and as anti-static agents, detergents and softeners for laundry products. Other uses will be obvious to those of skill in the art.
Optionally, the amino siloxane alkoxylates may be blended with other nonionic, cationic or anionic co-surfactants, especially those with hydrophobez of C5-C10 (short chain alkoxylates) and GEMINI surfactants (see WO 97/23281).